\input figs

%\advance\lw by -\unitindent

\newdimen\tal \tal=70pt % text arrow length
\dh = .3\fbh

\def\tarrow#1{\hbox to \tal
   {$\leftarrow$%
    \hss\hbox{\figfont #1}\hss
    $\rightarrow$}}
\def\arrow{\tarrow{}}
\def\daline#1 #2 #3 {\hbox to \hsize
   {\vrule width\lw \tarrow{#1}{#2}\tarrow{#3}\vrule width\lw}}
\def\bline{\hbox to \hsize
   {\vrule width\lw height.6\dh depth.3\dh
    \hfil.\hfil \vrule width\lw}}
\newbox\dbox
\setbox\dbox\hbox{$\vcenter{\vbox to \dh
              {\hsize=1pt \hrule height0pt depth\lw \
               \vfil \hrule height\lw}}$}
%\figure{
    \daline{}
           {{\tal=80pt \tarrow{parindent}}%
            \vrule width\lw
            \leaders\copy\dbox\hfil
            \vrule width\lw
            }
           {}
    \kern-\lw
    \daline{leftskip}
           {\vrule width\lw
            \leaders\copy\dbox\hfil
            \vrule width\lw
            }
           {rightskip}
    \kern-\lw
    \daline{}
           {\vrule width\lw
            \leaders\copy\dbox\hfil
            \vrule width\lw} {}
    \kern-\lw
    \bline \bline \bline \bline
    \daline{}
           {\vrule width\lw
            \leaders\copy\dbox\hfil
            \vrule width\lw} {}
    \kern-\lw
    \daline{}
           {\vrule width\lw
            \leaders\copy\dbox\hfil
            \vrule width\lw} {}
    \kern-\lw
    \daline{}
           {\vrule width\lw
            \leaders\copy\dbox\hfil
            \vrule width\lw
            {\tal=90pt \tarrow{parfillskip}}%
            }
           {}
    \hbox to \hsize{\vrule width\lw
       $\longleftarrow$\hfil
       \setbox0=\hbox{\figfont hsize}\ht0=15pt
       \box0
       \hfil$\longrightarrow$%
       \vrule width\lw}
%    }

